如何在使用javascript完成函数后获取全局变量值

var globalVariable = "Hello, world!";

function getGlobalVariable() {
  return globalVariable;
}

var result = getGlobalVariable();
console.log(result); // 输出：Hello, world!

var globalVariable = "Hello, world!";

function getGlobalVariable() {
  return window.globalVariable;
}

var result = getGlobalVariable();
console.log(result); // 输出：Hello, world!

var globalVariable = "Hello, world!";

function getGlobalVariable(variable) {
  return variable;
}

var result = getGlobalVariable(globalVariable);
console.log(result); // 输出：Hello, world!